The chemical amplification positive resist composition is a pattern forming material which is sparingly soluble or insoluble in a developer immediately after the formation on a substrate but when irradiated with radiation such as far ultraviolet light, produces an acid in the exposed area and through a reaction using this acid as the catalyst, increases the solubility in a developer of the area irradiated with actinic radiation, thereby forming a pattern on the substrate. Also, the chemical amplification negative resist composition is a pattern forming material which is easily soluble in a developer immediately after the formation on a substrate but when irradiated with radiation such as far ultraviolet light, produces an acid in the exposed area and through a reaction using this acid as the catalyst, decreases the solubility in a developer of the area irradiated with actinic radiation, thereby forming a pattern on the substrate.
In general, the chemical amplification resist composition for the processing using a light source (radiation source) such as KrF excimer laser, ArF excimer laser, F2 excimer laser, EUV (extreme ultraviolet light) and EB (electron beam) comprises, for example, a resin component, an acid generator component capable of generating an acid upon exposure, and an organic solvent capable of dissolving these components. Such a chemical amplification resist composition is required to give a resist pattern with high resolution, high sensitivity and good profile.
In the case of using an ArF excimer laser (193 nm) as a light source having a short wavelength for the exposure light source, since an aromatic group-containing compound substantially has large absorption in the 193-nm region, a resist containing a resin having an alicyclic hydrocarbon structure is being developed for use with an ArF excimer laser (see, for example, JP-A-9-73173 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”)).
It has been found that the performance can be enhanced by incorporating a repeating unit having a lactone structure into the above-described resin having an alicyclic hydrocarbon structure. For example, in JP-A-2005-97533, U.S. Pat. No. 6,388,101, JP-A-2000-159758, JP-A-2001-109154 and U.S. Patent Application Publication No. 2001-26901), a resist composition containing an acid-decomposable resin having a lactone structure is described.
On the other hand, in JP-A-2005-234330, a plurality of solvents are used with an attempt to enhance the image performance.
However, in view of integrated performance as the resist, an appropriate combination of the resin, photo-acid generator, additive, solvent and the like used is actually very difficult to find out, and moreover, at the formation of a fine pattern with a line width of 100 nm or less, even when the resolving performance is excellent, if the line width uniformity of the line pattern formed is bad, an electrical characteristic failure is brought about, giving rise to decrease in the yield. Accordingly, it is demanded to enhance the line width uniformity.